Chemex Coffee Ratio
Calculator
Select your Chemex model, how many cups you want today, and your filter type. Get exact grams, tablespoons, a personalized pour sequence, and a complete brew guide built for your specific setup.
Chemex Ratio Calculator
8 steps to your perfect brew
Chemex Coffee Ratio Quick Reference
All volumes use the Chemex native 5 oz cup (150 ml). Real mug counts use a standard 240 ml (8 oz) mug. All based on the bonded paper filter at 1:15 balanced ratio.
By Model at Balanced 1:15 Ratio
| Model | Capacity | Coffee (g) | Tablespoons | Bloom (ml) | Brew Time | Real 8oz Mugs |
|---|---|---|---|---|---|---|
| 3-Cup Classic | 450 ml | 30 g | 5 tbsp | 75 ml | 3:30-4:30 | 1.9 mugs |
| 6-Cup Classic | 900 ml | 60 g | 10 tbsp | 150 ml | 4:00-5:30 | 3.75 mugs |
| 8-Cup Classic | 1,200 ml | 80 g | 13.5 tbsp | 200 ml | 5:00-6:30 | 5 mugs |
| 10-Cup Classic | 1,500 ml | 100 g | 16.5 tbsp | 250 ml | 5:30-7:00 | 6.25 mugs |
| Metal Filter (-60s) | 900 ml | 60 g | 10 tbsp | 150 ml | 3:00-4:30 | 3.75 mugs |
By Strength (6-Cup / 900 ml)
| Strength | Ratio | Coffee | Tablespoons | Bloom | Flavor |
|---|---|---|---|---|---|
| Light | 1:17 | 53 g | 9 tbsp | 133 ml | Delicate, tea-like clarity |
| Balanced | 1:15 | 60 g | 10 tbsp | 150 ml | Full, sweet, specialty standard |
| Strong | 1:13 | 69 g | 11.5 tbsp | 173 ml | Bold, rich, good with milk |
| Extra Strong | 1:11 | 82 g | 13.5 tbsp | 205 ml | Intense, concentrated |
Iced Chemex Reference (1:10 Hot Concentrate Over Ice)
| Target Iced Volume | Coffee (g) | Hot Water | Ice Weight | Resulting Iced Coffee |
|---|---|---|---|---|
| 2 large glasses (600ml) | 40 g | 300 ml | 300 g | ~550 to 600 ml |
| 4 glasses (1,200ml) | 80 g | 600 ml | 600 g | ~1,100 to 1,200 ml |
| Full 6-cup Chemex | 60 g | 450 ml | 450 g | ~800 to 900 ml iced |
Why the Chemex Bonded Filter Changes Everything
No other common pour-over brewer requires this much attention to filter choice. Here is what the Chemex bonded paper does that nothing else replicates.
Chemex makes its own proprietary bonded paper filter, and it is not comparable to any standard #2 or #4 pour-over filter. The Chemex bonded filter is 20 to 30 percent thicker than the filters used in a Hario V60, Kalita Wave, or any standard cone dripper. That thickness does three things simultaneously: it slows the flow of water through the grounds, it removes a larger fraction of coffee oils (including most of the diterpenes that contribute to body), and it filters out virtually all fine particles.
The result is a cup that is exceptionally transparent. You can taste origin characteristics, roast character, and processing notes with unusual clarity because the filter has removed the oils and sediment that would otherwise mask or muddy those flavors. This is why Chemex has been a standard tool in coffee competitions and professional cuppings for decades. It produces the closest thing to a filtered laboratory extraction that home brewing allows.
The practical implication for your ratio and grind: because the filter slows flow, you need a coarser grind than you would use for any other pour-over. Using V60-appropriate medium-fine grind in a Chemex produces a brew time of 8 to 10 minutes and an astringent, over-extracted cup. Medium-coarse is the starting point. With a metal filter, the thick paper is gone and flow returns to normal pour-over speed, so you shift back to a standard medium grind.
How the Chemex Ratio Compares to V60 and Kalita Wave
People who switch to Chemex from V60 often ask why their previous V60 recipe tastes thin and underdeveloped in the Chemex. The answer is grind, not ratio. The ratio (1:15 for both methods) is essentially the same. The grind needs to be noticeably coarser for Chemex.
A V60 with a standard paper filter allows water to flow through at a fairly brisk pace. You compensate with a medium to medium-fine grind to ensure sufficient extraction. When you use the same grind in a Chemex with its thick bonded paper, the combined resistance of thick paper and fine grind slows the brew to a near-stall. Water sits in the filter for 8 to 10 minutes instead of 4 to 5, and the result is bitter, astringent, and completely undrinkable at any ratio.
The Kalita Wave sits between V60 and Chemex. Its flat-bed geometry and three-hole drain slow flow slightly compared to a conical V60, but nothing like the Chemex bonded filter. A slightly coarser grind than V60 works for Kalita, while Chemex needs significantly coarser still.
| Brewer | Ratio | Grind | Brew Time (6-cup) | Cup Body | Filter Type |
|---|---|---|---|---|---|
| Chemex (bonded paper) | 1:15 | Medium-coarse | 4:00-5:30 | Light, very clean | Proprietary bonded |
| Hario V60 | 1:15-1:16 | Medium-fine | 2:30-3:30 | Medium, clean | Standard paper |
| Kalita Wave | 1:15-1:16 | Medium | 3:00-4:00 | Medium-full | Standard paper |
| Chemex (metal filter) | 1:15 | Medium | 3:00-4:30 | Medium-full, some oils | Metal reusable |
| Clever Dripper | 1:14-1:15 | Medium | 3:30-4:30 | Fuller, immersion | Standard paper |
Getting Chemex Grind Size Right: Why Medium-Coarse and Not Medium
This is the single most important technical decision for Chemex. Every other pour-over brewer in common use works at medium or medium-fine. Chemex needs medium-coarse. This is not a preference, it is a requirement of the thick paper.
On most burr grinders, the difference between medium and medium-coarse is 2 to 4 clicks coarser than your V60 setting. The texture you are looking for is raw sugar or very coarse sea salt, with individual particles clearly visible and distinct. If you rub the grounds between your fingers and feel any powdery residue at all, the grind is too fine for Chemex bonded paper.
The diagnostic for grind is simple: time your total brew. With the bonded paper filter, a 6-cup Chemex should be complete in 4 to 5 minutes 30 seconds from first bloom pour to last drip. Under 3 minutes 30 seconds means grind finer. Over 6 minutes means grind coarser. Check your brew time before changing the ratio or water temperature. Brew time tells you everything about the grind.
For the metal reusable filter, return to a standard medium grind. The thick paper resistance is gone, so flow moves much faster. At medium-coarse with a metal filter, water rushes through the grounds in under 3 minutes and the cup tastes watery and sour.
The Chemex Bloom: Why It Uses More Water and Takes Longer Than Other Methods
Most pour-over methods use a bloom of 2 times the coffee weight and wait 30 to 35 seconds. Chemex is an exception on both counts. The standard Chemex bloom uses 2.5 times the coffee weight and rests for 45 to 50 seconds.
The reason is the thick bonded filter. When CO2 escapes from freshly roasted grounds during the bloom, it has to pass through not just the coffee bed but also a much thicker paper barrier. This slows the gas release slightly and means the grounds need more time to fully degas before the main pours begin. If you use a 30-second bloom in a Chemex, the remaining CO2 in the grounds creates uneven extraction channels during your main pours, producing a hollow, underdeveloped cup even with a perfect ratio and grind.
The extra water in the bloom (2.5x instead of 2x) ensures the thick paper gets fully saturated before the main pours start. A partially dry Chemex filter at the start of the main pour creates inconsistent resistance across the filter surface and leads to channeling on one side.
If your beans are very fresh (roasted within the past 3 to 5 days), extend the bloom rest to 55 to 60 seconds. The aggressive CO2 release from fresh beans is even more pronounced through a thick Chemex filter. Older beans (more than 4 weeks from roast) need only about 40 seconds because most CO2 has already dissipated.
Water Temperature for Chemex: Why You Need It Slightly Hotter Than V60
The thick bonded filter slows extraction. You compensate with slightly higher water temperature than most pour-over methods recommend.
These temperatures are 2 to 5 degrees higher than the equivalent recommendations for V60 or Kalita, precisely because the Chemex filter slows extraction. If you use V60-standard temperatures in a Chemex, the combination of thick paper and cooler water produces a thin, underdeveloped cup even when the ratio and grind are correct. Light roasts especially need the higher end of the range to fully develop their complex compounds through the dense paper barrier.
Without a thermometer: boil your water and rest it off heat for 10 seconds for light roast, 30 seconds for medium roast, and 50 to 60 seconds for dark roast. With a gooseneck kettle the pour takes long enough that the water cools slightly during the bloom, which is actually beneficial for medium and dark roasts.
How to Brew Iced Coffee in a Chemex
The Chemex is particularly well suited to iced coffee because the thick bonded filter removes the oils that can turn bitter when chilled. Fill the Chemex with a weight of ice equal to roughly half your target total liquid volume. Brew a hot concentrate at a 1:10 ratio directly over the ice. Use the same medium-coarse grind and water temperature as your hot brew. The hot concentrate drips onto the ice and chills on contact. The melting ice dilutes the concentrate to normal drinking strength.
For a full 6-cup Chemex iced batch: put 450 grams of ice in the Chemex, use 60 grams of coffee, and brew 450 ml of hot water over it. You end up with about 800 to 900 ml of finished iced coffee. The result is cleaner and less bitter than most cold brew methods because the bonded filter removes even more oils when the coffee is hot than when it is room temperature.
Chemex Model Guide: Which Size Is Right for How You Brew?
Every Chemex is borosilicate glass with a wood collar or glass handle and the same bonded paper. The differences are purely capacity.
3-Cup Classic or Glass Handle
The smallest full-featured Chemex. Max 450 ml. Brews 1.9 standard 8 oz mugs at full capacity. Uses the square or half-moon filter, not the circle filter used in larger models. Best for a single person who typically brews one strong mug or two lighter cups per session.
- Filter: Square or half-moon bonded
- Brew time: 3:30 to 4:30
- Best for: 1 to 2 people
- Coffee at 1:15: 30 grams
6-Cup Classic, Glass Handle, or Wood Collar
The most popular Chemex worldwide and the one most specialty coffee guides assume when writing ratio recommendations. Max 900 ml. Brews 3.75 standard mugs at full capacity. Multiple finish options: wood collar with leather tie, glass handle, or limited edition colors. Uses the #6 circle bonded filter.
- Filter: #6 circle bonded
- Brew time: 4:00 to 5:30
- Best for: 2 to 4 people
- Coffee at 1:15: 60 grams
8-Cup Classic
The least common standard size. Max 1,200 ml. Brews 5 standard mugs at full capacity. Uses the same #6 filter as the 6-cup. Good choice for households of 3 to 5 people who want to brew once and have enough for everyone. The 8-cup brews less awkwardly than the 10-cup at half-capacity.
- Filter: #6 circle bonded
- Brew time: 5:00 to 6:30
- Best for: 3 to 5 people
- Coffee at 1:15: 80 grams
10-Cup Classic
The largest standard Chemex. Max 1,500 ml. Brews 6.25 standard mugs. Uses the #6 filter. Best for households with 4 to 6 daily coffee drinkers or for entertaining. Requires more practice to pour evenly because of the longer spiral distance from center to edge of the bed.
- Filter: #6 circle bonded
- Brew time: 5:30 to 7:00
- Best for: 4 to 6 people
- Coffee at 1:15: 100 grams
Chemex Ottomatic
A machine that brews automatically into a standard 6-cup Chemex carafe. Maintains the correct water temperature and pours evenly over the grounds. Uses the same #6 bonded filter and the same 1:15 ratio as manual Chemex. Produces a comparable cup to a skilled manual pour without requiring technique.
- Filter: #6 circle bonded
- Same ratio as 6-cup manual
- Brew time: set by machine
- Best for: precision without technique
Choosing Between 6-Cup and 8-Cup
Most households overestimate how much coffee they brew per session. If you regularly brew for 2 to 3 people, the 6-cup is the right choice. It is easier to brew at near-full capacity, which produces more consistent extraction than brewing half a large carafe. The 8-cup is only worth it if you regularly need more than 800 ml per brew.
- 6-cup at full: 3.75 real mugs
- 8-cup at full: 5 real mugs
- Both use the same #6 filter
- Same ratio and grind for both
Chemex Troubleshooting Guide
Almost every Chemex problem traces back to grind size or water temperature. Work through one variable at a time.
The Gear That Makes Chemex Work
Priority order: scale first, then grinder, then kettle. The Chemex itself is obvious. These four additions complete the setup.
Five Things That Separate a Good Chemex from a Great One
Rinse the filter with water hot enough to actually pre-heat the glass
The Chemex glass carafe absorbs a surprising amount of heat from your first pour. If you rinse the filter with barely warm water, the glass is still cold when you start brewing. The first 100 to 150 ml of your bloom pour drops several degrees of temperature immediately. Rinse with fully boiling water, or at least the same temperature you plan to brew at. Pour at least 200 ml. Let it sit in the glass for 10 seconds before discarding. The pre-heated glass holds your brew temperature significantly better through the full 5-minute cycle.
Swirl the Chemex after the bloom rest
After the bloom rest, before your first main pour, give the Chemex one gentle circular swirl. This re-levels the coffee bed, closes any small channels that formed during the bloom, and distributes the remaining water in the grounds more evenly. You will notice the bed looks flatter after a swirl versus after a static bloom. That flat bed is your starting point for even extraction during the main pours. This technique is standard practice in specialty coffee circles and makes a measurable difference in the evenness of the finished cup.
Keep your pours slow and centered for the first pass
The most common pour-over pouring mistake in Chemex is starting the main pours too close to the edge of the filter. Pouring near the paper bypasses the coffee bed entirely and causes water to channel straight through the filter without extracting. Start every pour at the center of the bed. Move outward in a slow spiral that stops about 1 cm from the filter wall. The water will spread and saturate the outer grounds on its own. Pour the full volume for each pass, then wait. Do not add more water until the level in the filter has dropped by at least half.
Time every brew for the first month
Chemex is a method where the feedback loop is slow. You do not know if your ratio and grind are correct until the cup is finished. Timing the total brew from first bloom pour to last drip gives you instant diagnostic information without waiting to taste. If your 6-cup brew finishes in 3:15, grind finer. If it takes 6:45, grind coarser. Check brew time before adjusting anything else. Most Chemex problems that people blame on ratio or water temperature are actually grind problems that show up as off-target brew times.
Use beans that are 7 to 21 days from their roast date
Chemex extracts coffee more completely and more uniformly than most brew methods because of the slow, even flow through the thick paper. This means it reveals bean quality with unusual honesty. Fresh beans (3 to 7 days from roast) still release enough CO2 to cause uneven extraction even with a 50-second bloom. Stale beans (more than 30 days) produce a flat cup regardless of technique because the aromatic compounds have oxidized. The sweet spot is 7 to 21 days from roast, and the Chemex makes that window more obviously audible in the cup than a drip machine or French press would.
Frequently Asked Questions About Chemex Coffee Ratios
What is the best coffee ratio for a Chemex?
+The specialty coffee standard for Chemex is 1:15 to 1:16, meaning 1 gram of coffee per 15 to 16 grams of water. For a 6-cup Chemex at full capacity (900 ml), that is 56 to 60 grams of medium-coarse ground coffee. Chemex’s own printed recipe suggests approximately 1 heaped tablespoon per 5 oz of water, which lands near 1:15 to 1:17 depending on grind size. Weighing in grams is considerably more consistent than measuring tablespoons.
Why does Chemex use medium-coarse grind instead of medium like other pour-over methods?
+The Chemex bonded filter is 20 to 30 percent thicker than standard pour-over filters. That extra thickness significantly slows water flow through the grounds. If you grind at medium (appropriate for V60 or Kalita), the combined resistance of thick paper and medium grind produces a brew time of 8 to 10 minutes and an over-extracted, bitter cup. Medium-coarse compensates for the filter’s natural resistance and brings the brew time back into the 4 to 5 minute 30 second target range.
How much coffee for a 6-cup Chemex?
+A 6-cup Chemex holds 900 ml of liquid. At a 1:15 balanced ratio, use 60 grams of medium-coarse ground coffee. Your bloom pour should be about 150 ml (2.5 times the coffee weight) with a 45-second rest. A 6-cup Chemex at full capacity fills 3.75 standard 8 oz mugs, not 6, because each Chemex cup is 5 oz (150 ml).
Do I need to rinse the Chemex filter?
+Yes, always, and more thoroughly than you would for a standard pour-over filter. The Chemex bonded filter has a stronger paper flavor than V60 or Kalita filters because it is much thicker. Pour at least 200 ml of hot water through the empty filter in the Chemex, making sure to wet the paper on all sides. Discard the rinse water. For natural (brown, unbleached) filters, use 250 ml. This step also pre-heats the glass carafe, which matters for serving temperature of the first cup.
How long should a Chemex brew take?
+With the bonded paper filter: 3-cup takes 3:30 to 4:30, 6-cup takes 4:00 to 5:30, 8-cup takes 5:00 to 6:30, and 10-cup takes 5:30 to 7:00. These are total times from the first bloom pour to the last drip. With a metal reusable filter, subtract 60 to 90 seconds from all targets. Brew time is your primary diagnostic for grind. If outside the target range, adjust grind before changing anything else.
Does the Chemex metal filter change the ratio?
+The ratio stays at 1:15 but the grind needs to shift from medium-coarse to medium. Without the thick bonded paper slowing flow, water moves through the grounds at normal pour-over speed. At medium-coarse with a metal filter, the brew finishes in under 3 minutes and tastes sour and under-extracted. The metal filter also passes coffee oils into the cup, producing a noticeably fuller body and richer mouthfeel compared to the very clean, bright cup the bonded paper produces.
Why does my Chemex coffee taste bitter?
+Grind too fine is the cause in the majority of cases. This is the most common Chemex problem even among experienced pour-over brewers who switch from V60. Coarsen the grind two or three settings and time your next brew. If it now falls within the target range and the bitterness is reduced, you have found the answer. Other causes include water too hot for dark roast (drop temperature 5 degrees) or coffee sitting in the Chemex on a warming stand for more than 20 minutes after brewing.
How do I make iced coffee with a Chemex?
+Fill the Chemex with ice equal to roughly half your target final volume. Brew hot concentrate at a 1:10 ratio directly over the ice. For a full 6-cup Chemex iced batch: 450 grams of ice, 60 grams of coffee, and 450 ml of hot water. The hot concentrate chills on contact with the ice and the melting ice dilutes it to normal drinking strength. You end up with about 800 to 900 ml of finished iced coffee. Chemex is particularly good for this method because the bonded filter removes the oils that turn bitter and astringent when chilled.
Is Chemex better than V60 or Kalita Wave?
+Different, not better. Chemex produces the cleanest, most transparent cup of the three, which is excellent for light roasts with distinctive origin flavors. V60 produces more body than Chemex and is more forgiving of grind inconsistency. Kalita Wave is the most forgiving of the three and produces a slightly fuller body than V60. If you want the clearest possible cup with the most pronounced origin character, Chemex is the choice. If you want something between clean clarity and full body, V60. If you want consistency and forgiveness, Kalita. All three use essentially the same ratio (1:15 to 1:16).
What water temperature should I use for Chemex?
+Light roast: 205 to 208 F (96 to 98 C). Medium roast: 200 to 205 F (93 to 96 C). Dark roast: 195 to 200 F (90 to 93 C). These are 2 to 5 degrees higher than typical V60 recommendations because the thick Chemex filter slows extraction. Lower water temperature combined with a thick filter produces a thin, underdeveloped cup. If you do not have a thermometer, boil water and rest it for 10 seconds (light), 30 seconds (medium), or 55 seconds (dark) before pouring.
Can I use third-party filters in a Chemex?
+Yes, but the results will differ. Third-party #6 filters are typically thinner than Chemex’s bonded filters. A thinner filter produces faster flow, which shortens brew time and produces a slightly more oily, fuller-bodied cup compared to the classic Chemex result. If you use third-party filters regularly, you may need to grind slightly finer to compensate for the faster flow and maintain the same brew time target. The cup will taste closer to a standard pour-over than the ultra-clean Chemex result that the proprietary bonded filter produces.
Start Here and Adjust Once
Use 60 grams of medium-coarse coffee per 900 ml of water for a 6-cup Chemex. Rinse the filter thoroughly with 200 ml of hot water. Bloom with 150 ml and wait 45 seconds. Complete in two or three controlled pours, watching the scale to hit each target weight. Total brew time 4 to 5 minutes 30 seconds. Taste black. If it is bitter, coarsen the grind. If it is thin or sour, increase water temperature or fine the grind slightly.
Most people dial in their Chemex recipe within 3 to 5 brews. Once you find it, the recipe does not change unless you switch beans, roast levels, or filters. The calculator above recalculates everything automatically for any combination. Bookmark it for when you buy a new bag or change your setup.